首页
登录
职称英语
Scientists have long believed one way to stop the Earth’ s atmosphere from w
Scientists have long believed one way to stop the Earth’ s atmosphere from w
游客
2024-05-14
53
管理
问题
Scientists have long believed one way to stop the Earth’ s atmosphere from warming is by planting more trees. The idea is that more trees will take in or absorb stone of the carbon dioxide in the atmosphere. Carbon dioxide is a gas released by cars, factories and other human activities. The gas traps heat in the Earth’ s atmosphere, which warms tile planet. However, two new studies have found that trees may not be as helpful in reducing carbon dioxide as had been thought.
The first study was done at Duke University in Durham, North Carolina. Researchers pumped extra carbon dioxide into a test area where pine trees were growing. The trees grew thirty -four percent faster during the first three years. However, in time, the trees slowed to about their normal growth rate. The scientists say this is because trees need other nutrients, such as nitrogen.
In the second study, researchers from Duke and Bowdoin College in Brunswick, Maine examined the soil around trees. They discovered that as the leaves broke down into the soil, all the carbon was not trapped in the soil. Much of it was released into the atmosphere as carbon dioxide.
The findings of the two studies were published last month in Nature magazine. They suggest there is limited value in planting trees to reduce the carbon dioxide pollution in the atmosphere.
Forest planting has been a part of negotiations on a world agreement to reduce greenhouse gases that scientists believe cause global warming. The United States, Canada, Japan and some other industrial countries have supported the idea. But this new research suggests the idea is not as effective as environmental activists had thought. Scientist Ram Oren of Duke University led the study on tree growth. He says that earlier estimates on the ability of forests to absorb carbon dioxide were overly hopeful. Some scientists not involved in the studies say the research provides some of the first evidence on how trees react to carbon dioxide. Other scientists say the research disputes a belief among some coal and power companies. The companies say that rising levels of carbon dioxide in the atmosphere will not create harmful global warming. Instead, they say it will increase forests and other plants. [br] The word "it" (Line 3, Para. 6) probably refers to ______.
选项
A、carbon dioxide
B、nitrogen
C、atmosphere
D、coal
答案
A
解析
关键语句:“The companies say that rising levels of carbon dioxide in the atmosphere will not create harmful global warming.Instead,they say it will increase forests and other plants.”可见应是二氧化碳,其余选项与本段无关。
转载请注明原文地址:http://tihaiku.com/zcyy/3598237.html
相关试题推荐
[originaltext]Americanscientistsaredevelopingmapsthatcanidentifyare
[originaltext]Americanscientistsaredevelopingmapsthatcanidentifyare
ManyleadingscientistsdownthroughtheyearsfromGalileotoEinsteinhave
ManyleadingscientistsdownthroughtheyearsfromGalileotoEinsteinhave
ManyleadingscientistsdownthroughtheyearsfromGalileotoEinsteinhave
ManyleadingscientistsdownthroughtheyearsfromGalileotoEinsteinhave
ManyleadingscientistsdownthroughtheyearsfromGalileotoEinsteinhave
Scientistshavecomeupwithatheoryforwhytimeflieswhenyonarehaving
Scientistshavecomeupwithatheoryforwhytimeflieswhenyonarehaving
Scientistshavecomeupwithatheoryforwhytimeflieswhenyonarehaving
随机试题
Lifeasawomaninthecolonial(殖民的)Americaseemsquitedifferentfromit
ForgetexpensiveeducationalDVDsandprivatetutors,thesecrettosmartch
[originaltext]M:Why,MarySmith.Ihaven’tseenyouforages.Howhaveyoubee
Whenolderpeoplecannolongerremembernamesatacocktailparty,theyten
施工图预算的二级预算编制形式是指()。A:编制人编制、审核人审核 B:建筑安
上述各项,属亡阳证特征性表现的是( )。A.肌肤灼热,烦躁不安 B.胸腹灼热
根据《商业银行房地产贷款风险管理指引》,下列关于商业银行个人住房贷款申请人住房贷
下列情形中,注册会计师可能认为需要审计报告中增加强调事项段的是( )。A.被审计
某企业期初无存货,本期陆续购进批存货,发出批,在本期物价持124续上升的
某分部工程由4个施工过程组成,分为3个施工段组织流水施工,其流水节拍(天)见下表
最新回复
(
0
)